Image forming apparatus having a switching member, a detachable unit, and a retracting member that retracts the switching member in a course of dismounting the unit

ABSTRACT

An image forming apparatus including an apparatus main body including an image forming device that forms an image on a recording material, a unit detachably mounted in the apparatus main body, a switching member pivotably provided in the apparatus main body, wherein while in a state in which the switching member has entered into the unit mounted in the apparatus main body, the switching member selectively switches a route through which the recoding material is guided, and a retracting member provided in the apparatus main body, wherein in a course of dismounting the unit from the apparatus main body, the retracting member retracts the switching member to an outside of a mount area of the unit.

BACKGROUND OF THE INVENTION Field of the Invention

The present disclosure relates to an image forming apparatus such as acopier or a printer that includes a switching member to selectivelyswitch a route through which a recording material is guided, and a unitthat is capable of being mounted and dismounted to and from an apparatusmain body.

Description of the Related Art

Hitherto, an image forming apparatus such as a copier or a printer thatincludes a flapper to selectively switch a route through which arecording material is guided, and a fixing device that is capable ofbeing mounted and dismounted to and from an apparatus main body has beenproposed. An image forming apparatus adopting such a relationshipbetween the flapper and the fixing device capable of being mounted anddismounted is known in Japanese Patent Laid-Open No. 2014-130376.Furthermore, Japanese Patent Laid-Open No. 2016-75752 describes an imageforming apparatus that includes a fixing device that can be mounted anddismounted to and from an apparatus main body.

In other words, in view of the replaceability and ease of operation whenpaper is jammed, there is a need to facilitate mounting and dismountingof the fixing device mounted and dismounted to and from an image formingapparatus main body and the opening and closing unit without having tofeel any stress.

Referring to FIGS. 17 and 18, a configuration described in JapanesePatent Laid-Open No. 2014-130376 will be described. As illustrated inFIGS. 17 and 18, a cover 200 is provided so as to be openable andclosable with respect to an image forming apparatus. During the paperjam process and when replacing the fixing device, the cover 200 isopened as illustrated by broken lines in FIG. 18. Accordingly, inassociation with the opening movement of the cover 200, a flapper 202situated downstream of a fixing device 201 in a conveyance direction ofthe recording material is freed from the restriction of an abutmentportion 200 a included in the cover 200, and moves to a retractedposition. With the above, the fixing device 201 can be mounted anddismounted without coming into contact with the flapper 202.

Meanwhile, the weight of the image forming apparatus main body needs tobe reduced by reducing the size of the image forming apparatus main bodyand simplifying the component configuration to save the installationspace and to save energy during physical distribution.

However, as described in Japanese Patent Laid-Open No. 2014-130376, in aconfiguration in which the flapper 202 moves to the retracted positionwhen the cover 200 is released, the abutment portion 200 a for theflapper 202 to abut against the cover 200 is needed. In particular, in acase in which the flapper is disposed deep inside the image formingapparatus main body, the abutment portion also needs to be disposed at aposition deep inside the image forming apparatus main body.

In other words, in the configuration in Japanese Patent Laid-Open No.2014-130376, the pivoting locus of the cover 200 including the abutmentportion 200 a for the flapper 202 to abut against becomes large, and thesize of the image forming apparatus main body becomes large.Furthermore, in order to make the pivoting locus smaller, a complex linkconfiguration can be used; however, a large number of components will berequired which leads to an increase in the weight of the image formingapparatus.

SUMMARY OF THE INVENTION

The present disclosure suppresses increase in a size and weight of animage forming apparatus main body.

The present disclosure provides an image forming apparatus including anapparatus main body including an image forming device that forms animage on a recording material, a unit detachably mounted in theapparatus main body, a switching member pivotably provided in theapparatus main body, wherein while in a state in which the switchingmember has entered into the unit mounted in the apparatus main body, theswitching member selectively switches a route through which the recodingmaterial is guided, and a retracting member provided in the apparatusmain body, wherein in a course of dismounting the unit from theapparatus main body, the retracting member retracts the switching memberto an outside of a mount area of the unit.

Further features of the present disclosure will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view illustrating an example ofthe image forming device.

FIG. 2 is a schematic view of the image forming apparatus in which aright cover is open.

FIG. 3 is a schematic view of a fixing device.

FIGS. 4A and 4B are perspective views of a pressure applying mechanismof the fixing device.

FIG. 5 is a cross-sectional view of the pressure applying mechanism ofthe fixing device.

FIG. 6 is a perspective view of the fixing apparatus.

FIG. 7 is a diagram of flapper abutment components equipped in thefixing device.

FIG. 8 is a schematic block diagram of a mounting and dismountingmechanism of the fixing device.

FIG. 9 is a diagram of components of a discharging and reversing unit ofthe image forming apparatus.

FIG. 10 is a diagram of components of a flapper pivoting link mechanismof the image forming apparatus.

FIG. 11 is a diagram of components of the discharging and reversing unitin the course of pulling out the fixing device.

FIG. 12A is a perspective view around the insertion link in a state inwhich the fixing device is mounted, and FIG. 12B is a perspective viewaround the insertion link in the course of pulling out the fixingdevice.

FIG. 13 is a diagram of components of the discharging and reversing unitin a state in which the fixing device has been pulled out.

FIGS. 14A and 14B are diagrams illustrating the manner in which thefixing device is mounted to or dismounted from the apparatus main body.

FIGS. 15A to 15C are diagrams illustrating movements of the flapperviewed from the apparatus front side.

FIGS. 16A to 16C are diagrams illustrating movements of the flapperviewed from the apparatus rear side.

FIG. 17 is an explanatory drawing of a conventional technique.

FIG. 18 is an explanatory drawing of a conventional technique.

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, referring to the drawings, preferred embodiments of thedisclosure will be exemplified in detail. Note that the dimensions, thematerials, and the shapes of the components and the relativeconfiguration of the components, and the like that are described in thefollowing exemplary embodiment are to be appropriately changed based onthe device, to which the present disclosure is applied, and variousconditions. Accordingly, unless otherwise specified in particular, thescope of the present disclosure is not intended to be limited by theexemplary embodiment described below.

Referring first to FIGS. 1 and 2, an overall configuration of an imageforming apparatus to which the present disclosure has been applied willbe outlined. FIG. 1 is a schematic cross-sectional view illustrating anexample of the image forming device. FIG. 2 is a schematiccross-sectional view of the image forming apparatus illustrated in FIG.1 in which a right cover has been opened. Note that when viewing theimage forming apparatus illustrated in FIG. 1 in a direction orthogonalto the sheet surface of FIG. 1, this side with respect to the sheetsurface of FIG. 1 is referred to as the front side of the apparatus andthat side with respect to the sheet surface of FIG. 1 is referred to asthe rear side of the apparatus.

As illustrated in FIG. 1, an image forming apparatus 100 includes anapparatus main body 101 including an image forming device 11 that formsan image on a recording material P such as a sheet of paper, and afixing device 30 that is detachable from the apparatus main body 101 andthat fixes an image on the recording material P. The apparatus main body101 includes a flapper 40 serving as a switching member that selectivelyswitches the route (conveyance path) through which the recordingmaterial P is guided. The flapper 40 serving as the switching member ispivotably provided in the apparatus main body 101. The fixing device 30according to the present exemplary embodiment is a unit that isdetachably mounted in the apparatus main body 101. Between a mountingand dismounting direction Ya and Yb of the fixing device 30 with respectto the apparatus main body 101, the dismounting direction is Ya, and themounting direction is Yb (see FIG. 2).

In the image forming device 11, process cartridges 11Y, 11M, 11C, and11K including photosensitive drums are disposed along an intermediatetransfer belt 11 a. In the process cartridge 11Y, a yellow toner imageis formed on the photosensitive drum and is primarily transferred to theintermediate transfer belt 11 a. In the process cartridge 11M, a magentatoner image is formed on the photosensitive drum and is primarilytransferred over the yellow toner image on the intermediate transferbelt 11 a. In the process cartridges 11C and 11K, a cyan toner image anda black toner image, respectively, are formed on the relevantphotosensitive drums, and are primarily transferred in a sequentialmanner onto the intermediate transfer belt 11 a in a similar manner atpositions that overlap the toner image on the intermediate transfer belt11 a.

Meanwhile, the recording material P that has been fed through thefeeding unit 10 stands by before a transfer portion 12, and is sent tothe transfer portion 12 at a timing matching the toner image on theintermediate transfer belt 11 a.

The toner images of four colors carried on the intermediate transferbelt 11 a are conveyed to the transfer portion 12, and is transferredall at once onto the recording material P that is, while overlapping theintermediate transfer belt 11 a, pinched between and conveyed throughthe transfer portion 12. Subsequently, by passing the recording materialP through the fixing device 30, the toner image is heat fixed to therecording material P, and when only one side is printed, the recordingmaterial P is discharged through a discharge roller 13. When therecording material is discharged through the discharge roller 13, theflapper 40 switches the conveyance path to a discharge roller 13direction as illustrated by a broken line in FIG. 1 so that therecording material P passes under the flapper 40. In a case ofdouble-side printing, after the front end of the recording material Phas passed through the flapper 40 that has switched the conveyance pathto a reversing roller 14 direction as illustrated in FIG. 1 and untilthe rear end of the recording material P reaches a reversing point B, areversing roller 14 conveys the recording material P in a reverse path141 direction. Subsequently, the orientation of the flapper 40 isswitched to a duplex conveying roller 15 direction with a switchingmechanism described later. In so doing, the reversing roller 14 reversesthe rotation direction so that the recording material P is switched backso that the rear end is situated at the front, and so that the recordingmaterial P passes over the flapper 40 and is conveyed in the duplexconveying roller 15 direction. Subsequently, the recording material Ppasses through a both-surface conveyance path 16, and passes once morethrough the image forming device 11, the transfer portion 12, and thefixing device 30. The discharge roller 13 is provided downstream of thefixing device 30 in a conveyance direction of the recording material andis a discharging member that discharges the recording material. Thereversing roller 14 is provided downstream of the fixing device 30 inthe conveyance direction of the recording material and is a reversingmember that conveys the recording material in a reversed manner byreversing the rotation direction.

Note that in the present exemplary embodiment, the position of theflapper 40 when the recording material P is conveyed in the duplexconveying roller 15 direction, and the position of the flapper 40 whenthe recording material is conveyed in the discharge roller 13 directionare the same as illustrated by the broken line in FIG. 1. Accordingly,at the above point, an operation of switching the position of theflapper 40 does not need to be performed. Accordingly, the recordingmaterial P that has passed through the fixing device 30 reaches theflapper 40 and is discharged in the discharge roller 13 direction.

Note that a right cover unit 60 including the transfer portion 12 andthe both-surface conveyance path 16 is, with respect to the imageforming apparatus main body 101, configured to be openable and closeableabout a right cover rotation center 61. As illustrated in FIG. 2, bysetting the right cover unit 60 in an open state with respect to theapparatus main body, the recording material remaining in the vicinity ofthe transfer portion when the sheet is jammed can be removed.Furthermore, the above allows the fixing device 30 to be dismounted fromthe image forming apparatus main body 101 in the dismounting directionYa, which makes it easier to remove the recording material P pinched bythe fixing device 30.

Incidentally, an operation guide to the user when the paper is jammedand various setting of the image forming apparatus, for example, areperformed through an operation panel 80. For the sake of visibility ofthe operation panel 80 to the user and in order to efficiently use thespace, the operation panel 80 is disposed on the right side of adischarging and reversing unit including the discharge roller 13 and thereversing roller 14, in other words, the operation panel 80 is disposedabove the right cover unit 60. If the operation panel 80 rotatestogether with the right cover unit 60, the visibility will becompromised; accordingly, the operation panel 80 is disposed so as to befixed to the image forming apparatus main body 101. Accordingly, thedischarging and reversing unit including the discharge roller 13 and thereversing roller 14 is also disposed so as to be fixed to the imageforming apparatus main body.

Schematic Configuration of Fixing Device

Referring next to FIGS. 3, 4A, 4B, and 5, the fixing device 30 that is aunit that is detachably attachable to the image forming apparatus mainbody will be described. FIG. 3 is a schematic view of the fixing devicein the image forming apparatus. FIGS. 4A and 4B are perspective views ofa pressure applying mechanism of the fixing device. FIG. 5 is across-sectional view of the pressure applying mechanism of the fixingdevice.

As illustrated in FIG. 3, the fixing device 30 includes a heating filmassembly 302 serving as a heating rotation member, and a pressurecontact roller 303 that is a pressing rotation member that comes inpressure contact with the heating film assembly 302. The fixing device30 pinches and conveys the recording material P having a toner imagewhile heating the recording material P, and fixes the toner image withthe heating film assembly 302, the pressure contact roller 303. An entryguide 317 that guides the recording material to a nip portion N betweenthe heating film assembly 302 and the pressure contact roller 303 isdisposed upstream of the nip portion N in the conveyance direction ofthe recording material. A fixing device sheet discharge guide 310 and afixing device reverse guide 311 are disposed downstream of the nipportion N in the conveyance direction of the recording material. Thefixing device sheet discharge guide 310 is a first guide member thatguides the recording material P from the nip portion N in the dischargeroller 13 direction. The fixing device reverse guide 311 is second guidemember that, while guiding the recording material P from the nip portionin the reversing roller 14 direction, guides the switched back recordingmaterial P in the duplex conveying roller 15 direction. The fixingdevice reverse guide 311 is provided upstream of the fixing device sheetdischarge guide 310 in a direction (the arrow Yb direction in FIG. 2) inwhich the fixing device is mounted or inserted in the apparatus mainbody and is provided so as to oppose the fixing device sheet dischargeguide 310. A fixing device upper reverse guide 312 is disposed oppositethe fixing device reverse guide 311 with the both-surface conveyancepath 16 in between.

Pressure Applying Configuration

As illustrated in FIGS. 4A and 4B, both end portions of the pressurecontact roller 303 is rotatably supported by bearings (not shown) thatare attached to fixing apparatus side plates 339 fixed inside the fixingdevice 30. The heating film assembly 302 serving as a heating member issupported by the fixing apparatus side plates 339 in a direction havingthe heating film assembly 302 to be in pressure contact with thepressure contact roller 303. A fixing device nip portion is formed byapplying pressure to film regulating members 337 with pressure applyingplates (a portion of the pressure applying mechanism) 322 and 323. Firstends of the pressure applying plates 322 and 323 are engaged to holes341 and 351 (FIG. 5) of support frames 324 and 325 attached to thefixing apparatus side plates 339. Pressure applying springs (a portionof the pressure applying mechanism) 340 that apply pressure to the filmregulating members 337 while rotating the pressure applying plates 322and 323 about rotation centers of the holes 341 and 351 are providedbetween the support frames 324 and 325 and the pressure applying plates322 and 323.

Note that a large pressure generally needs to be applied to the nipportion to pinch and convey a recoding material P having a toner imagethereon while heating the recording material P and, on the other hand,the pressure of the nip portion needs to be reduced during the jammedpaper removing process when the user is removing the recoding material Ppinched in the nip portion.

Accordingly, the fixing device 30 includes a pressure-changing mechanismthat changes the pressure exerted on the fixing device nip portion. Thepressure-changing mechanism includes cams 328 and 329 serving as cammembers that act on the pressure applying mechanism. Pivoting of thecams 328 and 329 acts on the pressure applying plates 322 and 323 thatare a portion of the pressure applying mechanism, and the pressureexerted on the fixing device nip portion N can be reduced.

The cams 328 and 329 serving as cam members that act on the pressureapplying mechanism are fixed to both sides of a cam rotating shaft 350.The cam rotating shaft 350 includes, on one side thereof, a gear 315that transmits the drive to the rotating shaft.

Furthermore, the fixing device 30 includes a gear 314 that drives thepressure contact roller 303. The fixing device 30 is configured so thatdrive force from a motor (not shown) serving as a drive source providedin the image forming apparatus main body 101 is transmitted to the gears315 and 341.

As described above, a large pressure needs to be applied to the nipportion to pinch and convey the recording material P having a tonerimage thereon while the recording material P is heated. As illustratedin FIG. 5, in order to efficiently exert pressure, a distance L2 betweeneach pressure applying spring 340 and the rotation center of thecorresponding one of the pressure applying plate 322 and 323 needs to belarger than a distance L1 between the nip portion N and the rotationcenters of the pressure applying plates 322 and 323 (L2>L1).Furthermore, in order to efficiently reduce the pressure of the nipportion N during the jammed paper removing process, distances L3 betweenthe rotation centers of the pressure applying plates 322 and 323 and thecontact positions of the cams 328 and 329 need to be longer (L3>L2).

In other words, the nip portion N and the cam rotating shaft 350 of thecams 328 and 329 need to be disposed so as to be distanced away fromeach other.

(Cooling End Portions of Heating Film Assembly)

When recording materials P having a width that is small with respect tothe length of the heating film assembly 302 in the longitudinaldirection are continuously passed through, heat of the area in theheating film assembly 302 where the recording materials P pass is takenaway by the continuously passing recording material P. However, heat isaccumulated in the areas in the heating film assembly 302 where therecording materials P do not pass; accordingly, the above areas need tobe cooled. Accordingly, as illustrated in FIG. 3, front cover louvers354H that are air openings that cool the areas where the recordingmaterials P do not pass in the heating film assembly 302 are provided ina front cover 354.

Note that since the cam rotating shaft 350 needs to be disposed at aposition that does not get in the way of the air passage that cools theareas described above in the heating film assembly 302 where therecording materials P do not pass, the cam rotating shaft 350consequently needs to be disposed at the upper left portion in FIG. 3,in other words, in the vicinity of the discharge roller 13.

The fixing device sheet discharge guide 310 described above is disposedso as to cover the cam rotating shaft 350 so that the recording materialP proceeding in the discharge roller 13 direction does not becomecaught.

(Flapper Abutment Portion)

A component illustrated in FIG. 7 that is equipped in the fixing device30 and that abuts against the flapper 40 will be described.

A flapper pushing-up portion 311R and an insertion link pushing-upportion 311F that extend towards the cam rotating shaft 350 are providedat two ends of the fixing device reverse guide 311 in the longitudinaldirection. The flapper pushing-up portion 311R is provided on a firstside (apparatus rear side) in the longitudinal direction, and isdisposed so as to push up an abutment portion 402 of the flapper 40described later and to direct the recording material P conveyed from thefixing device nip portion towards the conveyance path extending in thedischarge roller 13 direction. The insertion link pushing-up portion311F is provided on a second side (apparatus front side) in thelongitudinal direction, and is disposed so as to push up a unitinsertion link 90 described later.

Furthermore, a flapper link 360, which is rotatably provided so as to berotated by a drive source described later, is provided on the camrotating shaft 350 and outside the flapper pushing-up portion 311R sothat the flapper 40 directs the conveyance path in the reversing roller14 direction.

Attaching and Detaching Mechanism of Fixing Device

Referring next to FIG. 8, a schematic configuration of a mechanism thatattaches and detaches the fixing device 30 to and from the image formingapparatus main body 101 will be described.

Main frame horizontal guide portions 112 and 122 serving as a pair ofattachment and detachment guides that support positioning pins 330 ofthe fixing device 30 are disposed in the image forming apparatus mainbody 101. The main frame horizontal guide portions 112 and 122 areprovided in the main frames 110 and 120 in a horizontal manner. Similarto the main frame horizontal guide portions 112 and 122, fixing devicerails 114 that guide guiding portions 355 of the fixing device 30 areprovided in the main frames 110 and 120 in a horizontal manner. Thefixing device 30 is movable in the mounting and dismounting direction Yaand Yb while maintaining a set position by having the positioning pins330 be guided by the main frame horizontal guide portions 112 and 122and, in a similar manner, by having the guiding portions 355 be guidedby the fixing device rails 114.

(Configuration of Discharging and Reversing Unit)

Illustrated next in FIG. 9 is an arrangement of the discharging andreversing unit disposed so as to be fixed to the image forming apparatusmain body 101, and the fixing device sheet discharge guide 310, thefixing device reverse guide 311, and the fixing device upper reverseguide 312 of the fixing device 30 disposed so as to be mountable anddismountable to and from the image forming apparatus main body 101. FIG.9 illustrates a state viewed from the apparatus front side in which thefixing device 30 is mounted in the image forming apparatus main body 101and a state in which the flapper 40 is switched to the positionillustrated by a broken line in FIG. 1. The position of the flapper 40illustrated in FIG. 9 is a position in which the recording material thathas passed through the fixing device is guided in the discharge rollerdirection, and a position in which the recording material conveyed afterbeing reversed by the reversing roller is guided in a duplex conveyingroller direction. FIG. 14A illustrates a state viewed from the apparatusrear side in which the fixing device 30 is mounted in the image formingapparatus main body 101 and a state in which the flapper 40 is switchedto the position illustrated by a solid line in FIG. 1. The position ofthe flapper 40 illustrated in FIG. 14A is a position in which therecording material that has passed through the fixing device is guidedin a reversing roller direction. Note that FIG. 14A illustrates theoverall fixing device 30 mounted in the apparatus main body 101.

The flapper 40 serving as the switching member is disposed on adischarging and reversing guide 51 with a flapper pivot shaft 41 inbetween and can be pivoted at a set angle. The discharging and reversingguide 51 is disposed so at to be fixed to a discharging and reversingframe 52. The flapper 40 is biased about the flapper pivot shaft 41 inan arrow E direction illustrated in FIG. 9 at all times with biasingforce of a biasing spring (a biasing member). When the fixing device ismounted in the image forming apparatus main body, the flapper 40 ispivoted to a direction opposite to the arrow E direction illustrated inFIG. 9 by having the flapper abutment portion 402 provided on theapparatus rear side of the flapper 40 abut against the flapperpushing-up portion 311R of the fixing device reverse guide 311.Accordingly, in a state illustrated in FIG. 9 in which the fixing deviceis mounted in the image forming apparatus main body, the flapper 40 isset at a position in which the conveyance path is set in the dischargeroller 13 direction. In the above state, the flapper 40 is at a positionillustrated in FIG. 9, and is at a first guiding position illustrated bythe broken line in FIG. 1. Accordingly, the recording material that haspassed between the nip portion of the fixing device passes through afirst conveyance path between one side of the flapper 40 at the firstguiding position and the fixing device sheet discharge guide 310, and isguided in the discharge roller 13 direction that is a first direction.

A front end portion 401 of the flapper 40 at the first guiding positionenters the fixing device, from a mounting and dismounting locus 310T ofthe uppermost point of the fixing device sheet discharge guide 310 inthe fixing device, in a direction intersecting the mounting anddismounting direction Ya and Yb by an overlapping amount T. Theoverlapping amount T illustrated in FIG. 9 is the amount in which thefront end portion 401 of the flapper 40 at the first guiding positionhas entered the fixing device, from the mounting and dismounting locus310T of the fixing device, in the direction intersecting the mountingand dismounting direction Ya and Yb.

Furthermore, in the above, the front end portion 401 of the flapper 40is set to overlap the fixing device reverse guide 311, as illustrated inFIG. 9, so that the front end of the recording material P exiting thenip portion of the fixing device 30 does not become caught. Note thatwhen the fixing device is mounted into the image forming apparatus mainbody, the uppermost point of the fixing device sheet discharge guide 310of the fixing device passes below the front end portion 401 of theflapper 40 that has been retracted to a retracted position describedlater. Subsequently, as described above, the flapper pushing-up portion311R of the fixing device abuts against the flapper abutment portion402. With the above, the flapper 40 at the retracted position ispivoted, and the front end portion 401 of the flapper 40 enters thefixing device by the overlapping amount T from the mounting anddismounting locus 310T of the uppermost point of the fixing device sheetdischarge guide 310. Furthermore, when the mounting of the fixing deviceis completed, the front end portion 401 of the flapper 40 overlaps thefixing device reverse guide 311 as illustrated in FIG. 9. Furthermore,the fixing device sheet discharge guide 310 of the fixing device 30 is,as described above, disposed so as to cover the cam rotating shaft 350.

On the other hand, in a state illustrated in FIG. 14A in which thefixing device is mounted in the image forming apparatus main body, theflapper 40 is switched to the reversing roller 14 direction with asolenoid 70 described later. In such a state, the flapper 40 is switchedto a second guiding position illustrated by the solid line in FIG. 1.Accordingly, the recording material that has passed between the nipportion of the fixing device passes through a second conveyance pathbetween the other side of the flapper 40 at the second guiding positionand the fixing device reverse guide 311, and is guided in the reversingroller 14 direction that is a second direction different from the firstdirection.

Furthermore, the flapper 40 that has been switched to the second guidingposition illustrated in FIG. 14A is, compared with the first guidingposition illustrated in FIG. 9, pivoted further in a direction oppositethe arrow E direction illustrated in FIG. 9. Accordingly, compared withthe first guiding position, the front end portion 401 of the flapper 40enters more into the fixing device. In other words, the front endportion 401 of the flapper 40 at the second guiding position enters thefixing device, from the mounting and dismounting locus 310T of theuppermost point of the fixing device sheet discharge guide 310 in thefixing device, in a direction intersecting the mounting and dismountingdirection Ya and Yb by an overlapping amount Tmax. The overlappingamount Tmax illustrated in FIG. 14A is the amount in which the front endportion 401 of the flapper 40 that has moved to a position illustratedby a solid line in FIG. 1 has entered the fixing device, from themounting and dismounting locus 310T of the fixing device, in thedirection intersecting the mounting and dismounting direction Ya and Yb.The relationship between the inroad amount of the flapper 40, into thefixing device, at the first guiding position illustrated in FIG. 9 andthe inroad amount of the flapper 40, into the fixing device, at thesecond guiding position illustrated in FIG. 14A satisfies T<Tmax. Inother words, compared with the first guiding position illustrated inFIG. 9, in the second guiding position illustrated in FIG. 14A, theflapper 40 enters more into the fixing device from the mounting anddismounting locus 310T of the fixing device, and the overlapping amountTmax is the largest inroad amount of the flapper 40.

FIG. 10 illustrates a link mechanism that pivots the flapper, viewedfrom the back side of the image forming apparatus main body 101. Thelink mechanism described hereinafter is a switching mechanism thatselectively switches the flapper 40, which is in a state in which thefront end portion 401 thereof has entered the fixing device 30 that hasbeen mounted in the apparatus main body 101, to a route (the conveyancepath) that the recording material is guided towards. The link mechanismincludes the solenoid 70 described later, a solenoid link 71, and theflapper link 360.

When the solenoid 70 disposed so as to be fixed to the image formingapparatus main body 101 is actuated to perform suction by having anelectrical signal sent thereto, the solenoid link 71 pivots and pushesone end of the flapper link 360 down, and a flapper link front endportion 361 on the other end pushes the flapper abutment portion 402 up.With the above, the flapper 40 is set at a position in which theconveyance path is set in the reversing roller 14 direction.

By stopping sending the electric signal to the solenoid 70, thesuctioning is stopped, and the sheet conveyance path of the flapper 40is returned to the discharge roller 13 direction with the biasing forceof the biasing spring (not shown) described above.

(Dismounting Fixing Device)

FIGS. 11 and 14B illustrates a process of dismounting the fixing device30 from the image forming apparatus main body 101. Note that FIG. 11illustrates the fixing device sheet discharge guide 310, the fixingdevice reverse guide 311, and the fixing device upper reverse guide 312of the fixing device 30. FIG. 14B illustrates an overall fixing device30 in the course of dismounting the fixing device 30 from the apparatusmain body 101.

As illustrated in FIGS. 11 and 14B, in the course of dismounting thefixing device 30 from the image forming apparatus main body 101, theabutment portion 402 of the flapper 40 is released from the flapperpushing-up portion 311R of the fixing device reverse guide 311.Accordingly, the flapper 40 can rotate to an angle at which the flapperfront end portion 401 does not overlap the fixing device sheet dischargeguide 310 in the direction intersecting the mounting and dismountingdirection Ya and Yb.

Typically, drive sources such as the solenoid 70 and the motor aredisposed in an area around the electric substrate to shorten the bundlewire thereof as short as possible. In other words, in the presentexemplary embodiment, since the electric substrate is disposed on therear side of the image forming apparatus, the solenoid 70 is alsodisposed on the apparatus rear side. Accordingly, the solenoid 70 isrequired to be as small as possible in the area on the apparatus rearside having a relatively small space. Furthermore, generally, since thesuction force of the solenoid changes according to the winding number ofthe coil built in the solenoid, the required suction force needs to beset small to reduce the size of the solenoid.

In the present exemplary embodiment, in order to keep the size of thesolenoid 70 described above small and efficiently decrease the size ofthe main body, flapper biasing force (force in the arrow E direction) bythe biasing spring applied to the flapper 40 is set small to restrictthe suction force needed when suctioning. Accordingly, the biasingspring is not set to have biasing force that biases the flapper frontend portion 401 to an angle, in other words, to and angle closed tohorizontal, that overlaps the flapper front end portion 401 over thefixing device sheet discharge guide 310 in the direction intersectingthe mounting and dismounting direction Ya and Yb.

The unit insertion link 90 serving as a retracting member is provided onthe apparatus front side of the apparatus main body 101. The unitinsertion link 90 is provided so that the unit insertion link 90 can beabutted or separated from the flapper 40. The unit insertion link 90 isbiased in a direction (an arrow F direction in FIG. 12A) that retractsthe flapper 40 to the outside of the mount area of the fixing device.When the fixing device 30 is pulled out from the apparatus main body101, the unit insertion link 90 reliably lifts up the flapper 40 to anangle at which the flapper front end portion 401 of the flapper 40 doesnot overlap the fixing device sheet discharge guide 310 in the directionintersecting the mounting and dismounting direction Ya and Yb. In otherwords, the unit insertion link 90 is a retracting member that, in thecourse of dismounting the fixing device from the apparatus main body,retracts the flapper 40 to the outside of the mount area of the fixingdevice in the apparatus main body. The unit insertion link 90 isprovided outside the recording material conveying area in a widthdirection orthogonal to the conveyance direction of the recordingmaterial. Note that the mount area of the fixing device is, asillustrated in FIG. 14B, an area 30T between the mounting anddismounting locus 310T of the uppermost point of the fixing device sheetdischarge guide 310 in the mounting and dismounting direction Ya and Yband a lower end portion of the fixing device. The outside of the mountarea to which the flapper 40 is retracted is the outside of a mount area30T. In further detail, the outside of the mount area to which theflapper 40 is retracted is, as illustrated in FIG. 14B, the outside (theupper side) of the mounting and dismounting locus 310T of the uppermostpoint of the fixing device sheet discharge guide 310 in the mounting anddismounting direction Ya and Yb. The flapper front end portion 401 ofthe flapper 40 is retracted to a position that does not overlap thefixing device sheet discharge guide 310 in the direction that intersectsthe mounting and dismounting direction Ya and Yb.

FIG. 12A illustrates a perspective view around the unit insertion link90 when the fixing device 30 is mounted in the image forming apparatusmain body 101. FIG. 12B illustrates a perspective view around the unitinsertion link 90 disposed on the front side of the fixing devicereverse guide 311, at a position of the fixing device 30 in FIG. 11 inwhich the fixing device is being pulled out from the image formingapparatus main body. Furthermore, FIGS. 15A and 16A illustrate the unitinsertion link while the fixing device is pulled out from the imageforming apparatus main body. FIGS. 15B and 15C, and FIGS. 16B and 16Cillustrate the unit insertion link in which the fixing device has beenmounted in the image forming apparatus main body. Furthermore, FIGS. 15Ato 15C illustrates the apparatus front side, and FIGS. 16A to 16Cillustrates the apparatus rear side. Note that the apparatus rear sideis one side of the fixing device reverse guide 311 illustrated in FIG. 7in the longitudinal direction on which the flapper pushing-up portion311R is provided. The apparatus front side is the other side of thefixing device reverse guide 311 illustrated in FIG. 7 in thelongitudinal direction on which the insertion link pushing-up portion311F is provided.

As illustrated in FIGS. 12A and 12B, the unit insertion link 90 isdisposed so as to be pivotable in a predetermined angle range about theflapper pivot shaft 41. Biasing force in the arrow F direction is actingon the unit insertion link 90 at all times. The unit insertion link 90is provided so that the unit insertion link 90 can be abutted orseparated from the flapper 40. Specifically, by pivoting the unitinsertion link 90, an insertion link abutment portion 91 of the unitinsertion link 90 becomes abutted against or separated from the flapperretraction abutment portion 403 of the flapper 40.

In the course of pulling out the fixing device from the image formingapparatus main body, as illustrated in FIG. 15A, the unit insertion link90 is detached from the insertion link pushing-up portion 311F of thefixing device. With the above, the insertion link abutment portion 91 ofthe unit insertion link 90 is abutted against the flapper retractionabutment portion 403 of the flapper 40 with biasing force of a biasingmember (not shown) and pushes up the flapper 40. With the above, asillustrated in FIG. 14B, the flapper 40 is retracted to the outside ofthe mount area 30T of the fixing device.

On the other hand, in a state in which the fixing device is mounted inthe image forming apparatus main body, as illustrated in FIGS. 15B and15C, the unit insertion link 90 is pushed up by the insertion linkpushing-up portion 311F of the fixing device. With the above, theinsertion link abutment portion 91 of the unit insertion link 90 isseparated from the flapper retraction abutment portion 403 of theflapper 40.

Furthermore, when the fixing device is mounted in the apparatus mainbody, as illustrated in FIG. 16C, the flapper pushing-up portion 311Rpushes up the abutment portion 402 of the flapper 40. With the above,the flapper 40 is switched to the first guiding position (the positionillustrated by the broken line in FIG. 1) that guides the recordingmaterial, which has passed through the nip portion of the fixing device,in the discharge roller direction. The recording material that haspassed between the nip portion of the fixing device passes through afirst conveyance path between one side of the flapper 40 at the firstguiding position and the fixing device sheet discharge guide 310, and isguided in the discharge roller 13 direction that is a first direction.In so doing, as illustrated in FIG. 15C, the insertion link abutmentportion 91 of the unit insertion link 90 is separated from the flapperretraction abutment portion 403 of the flapper 40.

Furthermore, in a state in which the fixing device is mounted in theapparatus main body, as illustrated in FIG. 16B, the solenoid link 71 ispivoted by the solenoid 70 (see FIG. 10) and the flapper link 360equipped in the fixing device lifts up the abutment portion 402 of theflapper 40. With the above, the flapper 40 is switched to the secondguiding position (the position illustrated by the solid line in FIG. 1)that guides the recording material, which has passed through the nipportion of the fixing device, in the reversing roller direction. Therecording material that has passed between the nip portion of the fixingdevice passes through the second conveyance path between the other sideof the flapper 40 at the second guiding position and the fixing devicereverse guide 311, and is guided in the reversing roller 14 directionthat is the second direction. In so doing, as illustrated in FIG. 15B,the insertion link abutment portion 91 of the unit insertion link 90 isseparated from the flapper retraction abutment portion 403 of theflapper 40.

Furthermore, the recording material that has been guided in thereversing roller 14 direction is conveyed in the reverse path 141direction with the reversing roller 14 before the rear end of therecording material reaches the reversing point B illustrated in FIG. 1.After the rear end of the recording material has reached the reversingpoint B, the flapper 40 is switched to the first guiding position (theposition illustrated by the broken line in FIG. 1). In so doing, thereversing roller 14 reverses the rotation direction so that therecording material P is conveyed in a reversed manner so that the rearend is situated at the front and so that the recording material P passesover the flapper 40 and is conveyed in the duplex conveying roller 15direction. In so doing, as illustrated in FIG. 15C, the insertion linkabutment portion 91 of the unit insertion link 90 is separated from theflapper retraction abutment portion 403 of the flapper 40.

Furthermore, in the course of dismounting the fixing device from theapparatus main body, as illustrated in FIG. 16A, the abutment portion402 of the flapper 40 is released from the flapper pushing-up portion311R of the fixing device. With the above, the flapper 40 can pivot toan angle at which the flapper front end portion 401 does not overlap thefixing device sheet discharge guide 310 in the direction intersectingthe mounting and dismounting direction Ya and Yb (see FIG. 14B).Furthermore, in the course of dismounting the fixing device from theapparatus main body, as illustrated in FIG. 15A, the unit insertion link90 is detached from the insertion link pushing-up portion 311F of thefixing device. With the above, the insertion link abutment portion 91 ofthe unit insertion link 90 is abutted against the flapper retractionabutment portion 403 of the flapper 40 with biasing force of a biasingmember (not shown) and pushes up the flapper 40 that has becomepivotable. In the above, as illustrated in FIG. 14B, the flapper 40 isretracted to the outside of the mount area 30T of the fixing device. Inother words, the flapper front end portion 401 of the flapper 40 isretracted above the mounting and dismounting locus 310T of the uppermostpoint of the fixing device sheet discharge guide 310.

As illustrated in FIG. 12A, in a state in which the fixing device 30 ismounted in the image forming apparatus main body 101, the insertion linkpushing-up portion 311F on the fixing device side abuts against the unitinsertion link 90 on the apparatus main body side. Furthermore, theinsertion link pushing-up portion 311F lifts up the unit insertion link90 in a direction opposing the biasing force in the arrow F direction.With the above, the insertion link abutment portion 91 of the unitinsertion link 90 and the flapper retraction abutment portion 403 of theflapper 40 become separated from each other, and the biasing force inthe arrow F direction acting on the unit insertion link 90 is nottransmitted to the flapper 40. Furthermore, in a state in which thefixing device is mounted in the apparatus main body, after the solenoid70 has performed suction to change the position of the flapper 40 to thereversing roller 14 direction, the insertion link abutment portion 91and the flapper retraction abutment portion 403 of the flapper 40 aredisposed so as to be separated from each other. Accordingly, the biasingforce in the arrow F direction acting on the unit insertion link 90 isnot transmitted to the flapper 40.

With the above, since the suction force needed in the solenoid 70 is notaffected by the biasing force in the arrow F direction acting on theunit insertion link 90, the size of the solenoid 70 can be kept evenmore small.

As illustrated in FIG. 12B, subsequently, in the course of pulling outthe fixing device 30 from the apparatus main body, the unit insertionlink 90 is released from the insertion link pushing-up portion 311F.Then, with the biasing force in the arrow F direction acting on the unitinsertion link 90, the insertion link abutment portion 91 of the unitinsertion link 90 abuts against the flapper retraction abutment portion403 of the flapper 40 and pushes the flapper 40 up in the arrow Fdirection. Furthermore, the retracted position of the flapper 40 is setby having the flapper 40 abut against a discharging and reversing frameabutment portion 521 of the discharging and reversing frame 52 with thebiasing force.

The state in which the flapper 40 is in the retracted position, in otherwords, a state in which the fixing device 30 has been pulled out fromthe image forming apparatus main body 101 is illustrated in FIG. 13.

The flapper front end portion 401 of the flapper 40 is sufficientlyretracted with respect to the mounting and dismounting locus 310T(illustrated in FIG. 13) of the uppermost point of the fixing devicesheet discharge guide 310 in the mounting and dismounting direction Yaand Yb. In other words, the flapper 40 is retracted to the outside ofthe mount area 30T (see FIG. 14B) of the fixing device 30 in theapparatus main body. Accordingly, when mounting and dismounting thefixing device 30, since the flapper front end portion 401 does not hitthe fixing device sheet discharge guide 310, in other words, the flapperfront end portion 401 does not hit the fixing device, mounting anddismounting can be carried out in a stress less manner.

As described above, in the course of pulling out the fixing device 30from the apparatus main body, the flapper front end portion 401 of theflapper 40 is configured to retract in the direction intersecting themounting and dismounting direction Ya and Yb. With the above, the sizeand weight of the image forming apparatus can be suppressed, andreplacement of the fixing device and the operation when the paper isjammed can be carried out smoothly.

In the exemplary embodiment described above, the insertion link 90 isdisposed on the apparatus front side where there is relatively plenty ofspace to efficiently suppress the overall size of the image formingapparatus; however, the configuration is not limited to the above. Forexample, when there is some unused space inside the apparatus, biasingforce E of the flapper 40 may be increased and the size of the solenoid70 can be increased without providing the insertion link 90.

Furthermore, in the exemplary embodiment described above, the fixingdevice has been exemplified as a unit that is detachably attachable tothe image forming apparatus main body; however, the configuration is notlimited to the above. A similar effect can be obtained by applying thepresent disclosure to a configuration in which another unit (theconveyance unit, or the like) is detachably attachable to the apparatusmain body and in which a flapper having a similar positionalrelationship as the unit described above is provided.

Furthermore, in the exemplary embodiment described above, the heatingfilm assembly has been exemplified as the heating rotation memberincluded in the fixing device; however, the configuration is not limitedto the above. The heating rotation member may be another heatingrotation member, such as a heat roller containing a heat generatingelement such as a heater, or may be an endless belt. Furthermore, thepressure contact roller 303 has been exemplified as the pressingrotation member included in the fixing device; however, theconfiguration is not limited to the above. The pressing rotation membermay be another pressing rotation member such as an endless beltincluding a portion applying pressure to the heating rotation member.

Furthermore, in the exemplary embodiment described above, the printerhas been exemplified as an image forming apparatus; however, theconfiguration is not limited to the above. For example, the imageforming apparatus may be another image forming apparatus such as acopying machine or a facsimile machine, or a multi-functional apparatusthat combines a plurality of the above functions. Similar effects can beobtained by applying the present disclosure to such image formingapparatuses.

While the present disclosure has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2017-170879 filed Sep. 6, 2017, Japanese Patent Application No.2018-117473 filed Jun. 20, 2018, which are hereby incorporated byreference herein in their entirety.

What is claimed is:
 1. An image forming apparatus comprising: anapparatus main body including an image forming device that forms animage on a recording material; a unit detachably mounted in theapparatus main body; a switching member pivotably provided in theapparatus main body, wherein while in a state in which the switchingmember has entered into the unit mounted in the apparatus main body, theswitching member selectively switches a route through which therecording material is guided; and a retracting member provided in theapparatus main body, wherein in a course of dismounting the unit fromthe apparatus main body, the retracting member retracts the switchingmember to an outside of a mount area of the unit.
 2. The image formingapparatus according to claim 1, wherein the retracting member isprovided so that the retracting member can be abutted against orseparated from the switching member, the retracting member being biasedto a direction that retracts the switching member to the outside of themount area of the unit, and wherein in a course of mounting the unit inthe apparatus main body, the retracting member is abutted against theunit and, countering biasing force, is separated from the switchingmember.
 3. The image forming apparatus according to claim 2, wherein ina course of dismounting the unit from the apparatus main body, theabutment between the retracting member and the unit is released, and theretracting member abuts against the switching member with the biasingforce and retracts the switching member to the outside of the mount areaof the unit.
 4. The image forming apparatus according to claim 2,wherein in a state in which the unit is mounted in the apparatus mainbody, the retracting member is separated from the switching member evenwhen the switching member has been switched.
 5. The image formingapparatus according to claim 1, wherein a switching mechanism thatselectively switches, in a state in which the unit is mounted in theapparatus main body, the switching member to a route through which therecording material is guided is provided separate from the retractingmember.
 6. The image forming apparatus according to claim 1, wherein theimage forming device included in the apparatus main body is configuredto form a toner image on a recording material, and the unit is a fixingdevice that fixes a toner image on a recording material.
 7. The imageforming apparatus according to claim 6, wherein the fixing device isconfigured to perform fixing of a toner image on a recording material bypinching and conveying the recording material with a heating rotationmember and a pressing rotation member while heating the recordingmaterial.
 8. The image forming apparatus according to claim 7, whereinthe switching member is capable of being switched between a firstguiding position that guides a recording material that has passedbetween the heating rotation member and the pressing rotation member toa first direction, and a second guiding position that guides therecording material to a direction different from the first direction. 9.The image forming apparatus according to claim 8, further comprising: adischarging member provided downstream of the fixing device in aconveyance direction of a recording material, the discharging memberdischarging the recording material; and a reversing member provideddownstream of the fixing device in the conveyance direction of therecording material, the reversing member reversing a rotation directionto convey the recording material in a reversed manner, wherein therecording material that has passed between the heating rotation memberand the pressing rotation member is guided in a discharging memberdirection with the switching member switched to the first guidingposition, and is guided in a reversing member direction with theswitching member switched to the second guiding position.
 10. The imageforming apparatus according to claim 9, wherein in a case in which animage is formed on each of the two surfaces of the recording material,the recording material that has passed between the heating rotationmember and the pressing rotation member is guided in the reversingmember direction with the switching member switched to the secondguiding position and, subsequently, is guided towards the image formingdevice once more by switching the switching member to the first guidingposition and by reversing the rotation direction of the reversingmember.
 11. The image forming apparatus according to claim 8, wherein ina course of mounting the fixing device in the apparatus main body, afront end of the switching member enters into the fixing device, and ina state in which the fixing device is mounted in the apparatus mainbody, the switching member is switched from the first guiding positionto the second guiding position so that an amount of the front endentering the fixing device is the largest.